Firearms, adapters for firearms and methods for using the same

ABSTRACT

A firearm and an adapter for use with a firearm is disclosed. The adapter includes a housing that surrounds at least a portion of a barrel of the firearm, wherein the housing further comprises a cylindrical exterior surface and at least one circumferential formation. The adapter also includes a receiver attached to the housing, wherein the receiver further comprises an interior surface that at least in part matches the exterior surface of the housing and at least one bore through which a coupling mechanism is inserted to couple the receiver to the at least one circumferential formation of the housing. The adapter serves to attach at least one accessory to the firearm.

RELATED APPLICATION

This patent is a continuation-in-part of International Patent Application Serial No. PCT/EP2004/003181, filed Mar. 25, 2004, which is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates generally to firearms and, more particularly, to firearms that are equipped with adapters to which accessories may be attached.

BACKGROUND

For many decades adapters have been used to attach accessories, such as, for example, night targeting devices, lighting units, bipod supports, grenade launchers or the like to firearms. In conventional firearms having steel casings, it is typical to attach an adapter, such as a telescopic sight adapter that is designed to support a telescopic sight for the firearm, directly on the steel casing. In addition to an adapter, the casing also houses a lock and fixedly supports a gun barrel. Consequently, exchanging the gun barrel is feasible only as part of extensive maintenance work.

Typically, with rapid-fire firearms, which have an extended outer housing, or casing, of sheet metal, an adapter for mounting accessories is attached on the outside of the outer casing of sheet metal. As with conventional firearms, the gun barrel of these rapid-fire firearms can be exchanged only as part of extensive maintenance work, if at all. Furthermore, under extreme conditions, the form and orientation of this sheet metal casing is not always perfectly stable relative to the gun barrel, which leads to changes in the position of the accessory (e.g., the sight) relative to the barrel, i.e., misalignment. Consequently, the targeting of the firearm may be affected. This is also true for modem rapid-fire firearms having plastic casings. Nonetheless, there has been no other option for the firearm designer but to attach the adapter or mounting unit for accessories directly on the casing.

For accessories that are attached to the front of the firearm, such as a laser targeting device, the orientation of the assembly, and thus the targeting device, is even more unstable if the accessory in question is not to be attached directly to the front segment of the barrel. However, attachment to the front segment of the barrel is undesirable, at least in precision firearms, because it degrades the achievable targeting precision. Thus, such a unit would have to be attached to a hand guard, the orientation of which relative to the barrel is even less precise than compared to when attached to the plastic casing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the front portion of an example rapid-fire firearm equipped with an example adapter.

FIG. 2 is an enlarged view of a portion of the front portion of FIG. 1.

FIG. 3 is an external view of the example firearm of FIG. 1 with a portion of the casing removed to expose a portion of the example housing.

FIG. 4 is a cross section along line IV-IV of FIG. 1.

FIG. 5 is a cross-sectional view of the firearm of FIG. 1 with an example front shaft attached to the example housing.

All figures show the same example firearm and example adapter. The scale of the figures varies, and the reference numbers are consistent in all figures. The firearm discharges from right to left in FIGS. 1-3 and 5.

DETAILED DESCRIPTION

Throughout this patent, position designations such as “above,” “below,” “top'” “forward,” “rear,” etc. are referenced to a firearm held in a normal firing position (i.e., pointed away from the shooter in a generally horizontal direction).

FIG. 1 shows a firearm 1 including an example adapter 8 disclosed herein for use with firearms to facilitate attachment of firearm accessories to, for example, a rapid-fire firearm 1. The adapter 8 includes a housing 9 and a receiver 10 that is mounted on the housing 9, both of which are described in greater detail below. Example accessories that are connectable to the receiver 10 of the adapter 8 include, for example, night targeting devices, lighting units, bipod supports, grenade launchers, or the like.

The example rapid-fire firearm 1 shown in FIGS. 1-3 is a gas pressure loader. The firearm 1 includes a pipe-shaped steel lock 12 that is molded into the interior of a plastic casing 144 at the rear end of a barrel 16. The lock 12 has locking pins (not shown) and is the central force-bearing component of the firearm 1. The lock 12 has male threads on the outer surface of its front end.

The housing 9 has a substantially cylindrical exterior surface and may be fabricated from steel, titanium, light metals, or any combination of various materials. The housing 9 includes a protuberance 18, which, when the housing 9 is installed, contacts the front of a shoulder 20 of the barrel 16. The housing 9 includes female threads that are firmly screwed onto the male threads of lock 12, thus forming a thread connection 22 and locking the shoulder 20 of the barrel 16 as described below. The contact between the lock 12, the shoulder 20, and the protuberance 18 makes the barrel 16 non-rotatable in the lock 12. Thus, the rear portion of the housing 9 operates like a coupling nut in combination with the lock 12.

Unlike a coupling nut, the housing 9 extends towards the front to contact or nearly contact a gas removal unit 24, which is removably mounted on the outside of the barrel 16. Though the housing 9 is relatively long, the contact between the shoulder 20 and the protuberance 18 assures an axially parallel and essentially coaxial orientation between the entire housing 9 and the barrel 16. The housing 9 surrounds the barrel 16 tightly without making contact with the barrel 16. The thread connection 22 between the housing 9 and the lock 12 likewise does not make contact with the barrel 16. In one example, the axial support of the housing 9 around the barrel 16 is provided only by the axial contact of the barrel shoulder 20 and the protuberance 18, and there is no contact in a radial direction. Thus, the barrel 16 is free to move and has the same characteristics as though a coupling nut were used, rather than the housing 9.

The housing 9 has a relatively thin perforated wall and two circumferential formations such as, for example, ring formations or grooves: a front ring groove 26, which may contain a slip gauge, and a larger rear ring groove 28. Due to the thinness of the wall of the housing 9, ring grooves 26, 28 are formed by grooves in the wall.

The barrel 16 has a radial gas discharge bore 30 in front of the cylindrical housing 9 that expands into the gas removal unit 24. An arrangement 32, including a gas piston 34, a shaft 36 and a spring 38, extends parallel to the barrel 16 behind the rear of the gas removal unit 24. The spring 38 contacts the casing 14 by a shim 40, while the shaft 36 extends into the casing 14. Though FIG. 2 shows the spring 38 in two positions, only one spring 38 is used.

If no receiver 10 is mounted on the housing 9 of the firearm 1, a conventional front shaft 41 (FIG. 5) may be attached to the housing 9. The front shaft 41 is not obstructed by the housing 9 in any manner. However, if, as shown in FIGS. 1-4, a receiver 10 is mounted on the housing 9, the receiver 10 may be implemented as a receiver 10 having for four axis-parallel rails 42, 44, 46. In this example, the receiver 10 is designed as a pipe-like housing made of aluminum, though other metallic materials, a plastic, or a plastic and metal combination may also be used. The receiver 10 has an inner bore 48 that fits precisely on the exterior of the housing 9 and is mounted onto the front of the housing 9 to form the adapter 8. The bore 48 has radial recesses 50 (FIG. 4), such that the receiver 10 may be mounted from the front over the gas removal unit 24 and the gas piston, shaft and spring arrangement 32 onto the housing 9.

The receiver 10 has three cross bores 52 a, 52 b, 52 c, which tangentially traverse the ring grooves 26, 28 and which are of substantially identical size. There is one bore 52 a, 52 b on each of the upper and lower surfaces of the housing 9 in the area of the front ring groove 26, while the third bore 52 c is placed in the area of the rear ring groove 28 over the housing 9. In one example, the distance between the ring grooves 15 and 17 is set to correspond to almost the entire length of the receiver 10.

There is a coupling mechanism, such as a fitted pin or screw 54 in the upper front bore 52 a, which fits exactly into the front ring groove 26. In the rear bore 52 c is another coupling mechanism, a loose pin 56, which has substantially the same dimension as screw 54, but because the rear groove 28 has a larger diameter than the front groove 26, the pin 56 has play, i.e., is not closely fitted into the rear ring groove 28. Consequently, the receiver 10 acts as a bridge with a solid connection 26, 54 and a loose connection 28, 56 axially, but which may essentially rotate with respect to the housing 9 in ring grooves 26, 28. Though the receiver 10 may essentially rotate with respect to the housing 9 in the ring grooves 26, 28, there is an extension 58 that extends beyond the rear end of receiver 10 that limits any rotation. The extension 58 fits into a corresponding recess 60 of the casing 14, which limits the rotation of the receiver 10 with respect to the housing 9.

The lower front bore 52 b is intended for a special use, such as for mounting accessories that may transfer significant forces to the firearm 1.

When the barrel 16 needs to be exchanged (e.g., for cleaning or repair), it necessary to remove the barrel 16 from the lock 12 and casing 14. In the illustrated example, the barrel 16 is removed by first removing the receiver 10 from the housing 9. This may be carried out by removing the pins 54, 56 that are inserted through the receiver 10 into the grooves of the housing 9. After the pins 54, 56 are removed, the receiver 10 may be slid forward on the firearm 1 over the gas removal unit 24.

After the receiver 10 has been removed, the housing 9 is rotated such that the threaded connection 22 loosens, thereby moving the protuberance 18 from the shoulder 20 of the barrel 16 and decoupling the housing 9 and the lock 12. Once the threads on the housing 9 and the lock 12 are no longer in engaged, the housing 9 may be removed and the barrel 16 may be slid out of the lock 12. A new barrel 16 may then be inserted into the lock 12. Then the housing 9 is inserted over the barrel 16 and rotated to engage the threads on the housing 9 with the threads on the lock 12 to re-form the threaded connection 22 and secure the shoulder 20 between the protuberance 18 and the lock 12. The receiver 10 may then be re-mounted to the housing 9 by sliding the receiver 10 over the gas removal unit 24 and reinstalling the pins 54, 56.

As previously mentioned and shown in FIG. 4, the receiver 10 has four rails, including the upper rail 42, two side rails 44, and a lower rail 46. An accessory may be pushed onto each of the rails 42, 44, 46 to be fastened therein by cross grooves 62. The rails 42, 44, 46 may be conventional rails such as, for example, Picatinny rails.

The illustrated example is particularly beneficial because the receiver 10 is bound to the housing 9 only axially. This allows the housing 9 to be screwed tightly onto the lock 12 (via the protuberance 18) to form thread connection 22, as described above. However, the exact final rotational position of the housing 9 is of no consequence to the proper and successful mounting and alignment of the receiver 10 because the receiver 10 can freely rotate about the housing 9, any resulting rotational alignment is acceptable due to the pair of complementary formations, the recess 60 and the extension 58. Once fully assembled, the extension 58 is bound within the confines of the recess 60 to ensure that the receiver 10 is properly aligned. The design of the recess 60 was considered and implemented in the production of the firearm 1 and may be a standard feature that appears on firearms that do not have the adapter 8.

FIG. 2 shows specifically that the loose connection (loose pin 56, ring groove 28) is designed to have not a circular profile, but, rather, be an extended oval groove 28. FIG. 2 also shows that the adapter 8 does not make contact with the gas removal unit 24. Thus, the solid connection of the gas removal unit 24 within the barrel 16 is not degraded or affected in any fashion by the addition of the adapter 8.

FIG. 4 shows a cross-sectional view of the firearm 1 along the IV-IV line in FIG. 1. An example receiver 10 can be seen here, the inner bore 48 of which circumfuses the housing 9. The recesses 50 of the bore 48 enable the receiver 10 to be mounted over the gas removal unit 24 during assembly or disassembly.

As stated above, the adapter 8 disclosed herein is used to attach accessories, such as night targeting devices, lighting units, two-leg supports, grenade launchers or the like, to a firearm 1, specifically a rapid-fire firearm 1. It is also possible to add other accessories like a separate hand protector on the lower rail 46, or behind the receiver 10.

As described herein, the receiver 10 may be constructed out of metal and mounted on the exterior of the housing 9, which has a substantially circular or ring formation. The housing 9 is also mechanically connected to the barrel 16, such that the housing 9 surrounds the barrel 16 and is oriented coaxially or axially parallel to the barrel 16. Further, the adapter 8 can accommodate accessory units and can support the accessories in a stable connection with respect to the casing 14.

In another example, the adapter 8, as described above, may also include an extension 58 that is operable within a recess 60 of the casing 14. The extension 58 and the recess 60 operate to limit rotation of the receiver 10, and, thus, any accessories attached thereto, relative to the housing 9 and the firearm 1.

The housing 9 has a solid mechanical connection with the barrel 16 with lock 12, such that the housing 9 is most stable, i.e., has a maximum rigidity, when fully connected to the barrel 16. Temperature changes, such as for example, those due to sunlight are not sufficient to modify the connection in any measurable manner.

As described above, the cylindrical exterior surface of the housing 9 and its circumferential grooves 26, 28 enable potential rotation of the receiver 10 with respect to the housing 9. The receiver 10 is fixed to the housing 9 in the axial direction of the barrel 16 by means of the ring grooves 26, 28, but the receiver 10 is not rotationally fixed with respect to the housing 9. To also fix the rotational position or limit rotational movement of the receiver 10 with respect to the housing and/or casing 14, the extension 58 extends into the recess 60 in the body of the firearm 1, i.e., its casing 14. The extension 58 and recess 60 may deform due to various heat influences, specifically if the recess 60 is formed in the plastic casing 14. However, any such deformation or modification of the extension 58 and recess 60 would only affect the rotational position of the receiver 10 relative to the axis of the barrel 16, but not the angular position. In other words, the angle between the axis of the gun barrel 16 and the axis of the adapter 8 is always constant. Normally, these axes coincide.

Any minor movement of the receiver 10 or a target point, for example by one or two tenths of a millimeter relative to the point of incidence, is totally insignificant compared to the other confounding factors. Of most importance, with respect to the stability and alignment of the receiver 10, are the length of the exterior surface of the housing 9, the matching of the extension 58 and the recess 60, and the precision of the positioning of the receiver 10 on the housing 9. If these parameters can assure that the receiver 10 does not wobble on the housing 9 (or does so at an acceptable minimal level), then there is no possibility for a change of the angle between the housing 9 or the receiver 10 in the direction of the axis of the barrel 16, and the adapter 8 is then practically fully (or acceptably) secured relative to the barrel 16.

Preferably the extension 58 and the recess 60 will be part of the original design of the firearm 1 to prevent rotation of the adapter 8. If, however, a firearm 1 is designed and manufactured without an extension 58 or recess 60, the extension 58 and the recess 60 may be produced later, such as by, for example, a drill.

One of ordinary skill in the art would appreciate that the example adapter 8 may be used with a rapid-fire firearm 1, such as, for example, a gas pressure loader. However, the example housing 9 and the example receiver 10 may also be attached to a machine gun, a sub-machine gun, a pistol, or the like without problems. To the extent that the free movement of the barrel 16 is not hindered, attachment of the adapter 8 to a sharpshooter firearm may also be appropriate.

As described herein, to facilitate a simple, but stable attachment of the receiver 10 to the housing 9, the illustrated example includes ring formations or grooves 26, 28 to which the receiver 10 may link. Further, the inner bore 48 of the receiver 10 complements, at least in part, the exterior surface of the housing 9. This optimizes the attachment of the receiver 10 on the housing 9 in a simple, but reliable manner.

In conventional firearms, particularly modern rapid-fire firearms, the gun barrel 16 is held in place by a coupling nut that surrounds the shoulder 20 of the barrel 16 on its rear section and that is screwed into male threads on the exterior surface of the lock 12, which is set in the plastic casing 14. The present example has the metal housing 9, which can be screwed onto the firearm 1, supporting the barrel 16, rather than the coupling nut holding the barrel 16. Additionally, because the housing 9 is not designed to support excessive loads, the housing 9 may be produced of light metal, such that it adds only an insignificant weight to the firearm 1.

As stated above, in the illustrated example, the barrel 16 is supported in the firearm 1 by the housing 9 instead of a conventional coupling nut. However, although the housing 9 extends for some length of the barrel 16, because the housing 9, just as the coupling nut, only contacts one shoulder 20 of the barrel 16, and nothing else, the barrel 16 is supported in the same fashion with the housing 9 as with the coupling nut. Thus, the housing 9 presents no impediment to free movement of the barrel 16 of the firearm 1.

As mentioned above, the illustrated example firearm 1 has two circumferential ring grooves in the housing 9, the smaller ring groove 26, which is towards the front, and the larger ring groove 28 towards the rear. The receiver 10 has corresponding recesses or bores 52 a, 52 b, 52 c that connect to the ring grooves 26, 28. Front bores 52 a, 52 b correspond to the smaller groove 26, and rear bore 52 c corresponds to the larger groove 28. The ring grooves 26, 28 have slightly larger diameters than the corresponding bores 52 a, 52 b, 52 c and pins 29, 31 are inserted through the bores 52 a, 52 b, 52 c and the grooves 26, 28 to couple the receiver 10 with the housing 9, as described herein. Thus, the illustrated example assures that locking and disengaging connectors are provided for the attachment of the receiver 10 in the ring formations 26, 28. In the front bores 52 a, 52 b and groove 26, the fitted pin 54 is secured as the connector, which creates a precise and solid attachment. In the rear bore 52 c and groove 28, the loose pin 56 is inserted as the connector. The loose pin 56 creates an attachment between the receiver 10 and the housing 9 that has a certain amount of friction in the direction of the axis of the barrel 16 such that the receiver 10 may move as a result of heat expansion in a specified direction with no effect on the targeting precision, in order to expand or contract relative to the casing 14 without restraint. Because the loose pin 56 connection in the rear bore 52 c and groove 28 allows for expansion and contraction of the receiver 10 and the housing 9 relative to each other, heat tension and resulting deflections that would otherwise lead to imprecision or other mechanical problems are avoided, and practically all damages from heat expansion are prevented. Care should be taken to ensure that the receiver 10 makes contact with such pins on two facing or opposite sides of the housing 9.

In an alternative example, it is possible to omit one of the ring formations 26, 28 and instead to provide a protuberance (not shown) or the like on the housing 9, which can then serve as the contact for the receiver 10. This protuberance may be flush against the receiver 10 and thus transfers heat away from the housing 9. Furthermore, in yet another alternative example, the receiver 10 may be designed with surface extensions, such as ribs, in order to improve heat dissipation.

Normally, a rapid-fire firearm 1 has a front shaft, which surrounds the barrel 16 at least partially, and which protects the hand of a user from being burned by a hot barrel 16. In the illustrated example, the adapter 8 may also provide protection for the hand of the user.

In an alternative example, discussed above, the housing 9 is mounted within the front shaft 41 (FIG. 5). The front shaft 41 may be design to removably fit over the housing 9. These designs enable modification of the firearm 1 without extensive maintenance. For example, if the front shaft 41 is removable, the adapter 8, and thus, various accessories, may be attached to the firearm 1 upon removal of the front shaft 41. This example may be used in conventional rapid-fire firearms as well as in future designs.

One example accessory is a grenade launcher, which may be attached on the underside of the barrel 16 especially where there are sights are mounted elsewhere on the firearm 1. The securely aligned and stable connection guaranteed by the adapter 8 is particularly beneficial when the accessory attached thereto is a grenade launcher because grenade launchers impart high forces to the firearm 1 and must always be oriented precisely. Further, the solid attachment guaranteed by the adapter 8, as described herein, is also beneficial for accessories that do not impart high forces on the firearm 1, such as for example, a bayonet for a shotgun.

One of ordinary skill in the art will also appreciate that the adapter 8 with rails 42, 44, 46 parallel to the axis of the barrel 16 is particularly advantageous, as the rails 42, 44, 46 may serve as support for various other accessories, such as, targeting units such as night vision targeting units, lighting units such as infrared lighting units with high output, a bi-pod or tri-pod support, a front pistol grip, a belt anchor, or the like. The rails 42, 44, 46 are particularly useful to attach these accessories and others to the firearm 1 quickly and simply. Further, the rails 42, 44, 46 can support many accessories, regardless of their weight. Preferably, the adapter 8 has four rails 42, 44, 46 that are equally spaced around the firearm 1 at equal angles from each other, thus one rail each above 25, below 27, and on the two sides 26, relative to the axis of the barrel 16. This makes it feasible to attach several accessories to the adapter 8 at the same time. The solid and secure connection of example adapter 8 guarantees that the adapter 8 can support high loads continuously and reliably, where these loads are directly transferred to the housing 9 that supports the barrel 16 and the lock 12, i.e. the component best suited to accept force. Also, it is, of course, possible to equip the adapter 8 with less than four rails, such as only a single rail.

Similar to the housing 9, the receiver 10 may consist of a light metal. However, it is advantageous that the receiver 10 consist of a hard, solid plastic because the receiver 10 is in contact with a substantial portion of the exterior surface of the housing 9, to provide added strength. The plastic may be reinforced, such as with sprayed-on fiberglass, or it may be Duroplast. The rails 25, 26, 27 may also be made of a reinforced plastic. Use of a reinforced plastic permits an economic and efficient manufacture of the receiver 10 and the rails 42, 44, 46 as well as a relatively simple attachment to the housing 9.

The receiver 10 may consist of two or more components, which are held together by fasteners, such as bolts and screws. These bolts may also project into the ring formations, preferably ring grooves 26, 28. However, it is optimal that the receiver 10 is just a single piece. Then the receiver 10 may be mounted over a detached gun barrel 16 and the housing 9 from the rear. However, it is optimal that the receiver 10 is designed to be mounted onto the housing 9 from the front over the barrel 16 and over additional components of the firearm 1 such as, for example, a silencer or, in the case of a gas pressure loading firearm 1, the gas transfer unit 24.

Further, the housing 9 is generally preferably perforated, specifically to reduce weight, improve cooling and to provide bore holes for use in attaching and specifically in loosening the housing 9.

As described above, the housing 9 may be used to modify a firearm 1 such as, for example, conventional gas pressure loading rapid-fire firearm 1. Traditional gas pressure loading rapid-fire firearms have barrels that may be removed by loosening a coupling nut. The firearm 1 may then be modified, according to the illustrated example, by adding a barrel 16 that is supported by a housing 9, in lieu of the coupling nut. Further, because the cylindrical housing 9 extends towards the front of the barrel 16 and has a cylindrical exterior surface, the receiver 10 and other accessories may be mounted onto the housing 9. As described above, the receiver 10 is mounted to the housing 9 via the fitted pin 29, which extends through the front bore holes 52 a and 52 b in the receiver 10 to secure the receiver 10 to the ring groove 26 in the housing 9, and the loose pin 56, which extends through the rear bore 52 c in the receiver 10 to secure the receiver 10 to the ring groove 28 in the housing 9. These connections secure the adapter 8 to the rapid-fire firearm 1 such that the adapter 8 is essentially permanently fixed, axially, yet may be axially rotated to some degree. This example may be used in any rapid-fire firearm 1, regardless of its method of operation.

The example adapter 8 is particularly advantageous for use with the rapid-fire firearms such as a gas pressure loading rapid-fire firearm 1 that has with bores 51 in the barrel 16 to vent the gas and a gas removal unit 24 on the barrel 16 because the receiver 10 maybe mounted onto the housing 9 over the gas removal unit 24 and dismounted, or exchanged without requiring that the barrel 16 or the gas removal unit 24 be modified or removed. In an alternative example, the receiver 10 may be separated lengthwise and may consist of two or three components that are mounted from the side to be linked to each other, such as by screws.

In sum, the present disclosure illustrates an example adapter 8 that is mounted to a firearm 1, particularly a rapid-fire firearm 1, to which one or more accessories may be fastened. The adapter 8 includes the housing 9 that may be made of metal and has a substantially cylindrical exterior surface that contains the front ring groove 26 and the rear ring groove 28. The housing 9 is mechanically connected with the barrel 16 of the firearm 1 such that the housing 9 surrounds the barrel 16, where the ring grooves 26, 28 are oriented axially or axis-parallel to barrel 16. The adapter 8 also includes the receiver 10, which may be attached solidly to housing 9 in order to support accessories. The adapter 8 also includes the protuberance 58 that engages the matching recess 60 to limit rotation of the adapter 8 with respect to the housing 9 and to keep the adapter aligned.

Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents. 

1. A firearm comprising: an adapter to attach at least one accessory, wherein the adapter comprises: a housing that surrounds at least a portion of a barrel of the firearm, wherein the housing further comprises a cylindrical exterior surface and at least one circumferential formation; and a receiver attached to the housing, wherein the receiver further comprises an interior surface that at least in part matches the exterior surface of the housing and at least one bore through which a coupling mechanism is inserted to couple the receiver to the at least one circumferential formation of the housing.
 2. The firearm according to claim 1, wherein the receiver is rotatable with respect to the housing.
 3. The firearm according to claim 1, wherein the receiver is axially fixed with respect to the housing.
 4. The firearm according to claim 1, wherein the rotational alignment of the receiver is independent of the position of the housing.
 5. The firearm according to claim 1, wherein the at least one accessory is at least one of a night targeting device, a lighting unit, a bi-pod support, a tri-pod support, a grenade launcher, a shotgun accessory, or a sight.
 6. The firearm according to claim 1, wherein the housing is mechanically linked to the barrel.
 7. The firearm according to claim 1, wherein the housing is axially parallel to the barrel.
 8. The firearm according to claim 1, wherein the receiver further comprises an extension that engages a recess in a portion of the firearm to limit rotation of the receiver.
 9. The firearm according to claim 1, further comprising a second circumferential formation.
 10. The firearm according to claim 1, wherein the housing further comprises a protuberance that serves as a contact for the receiver unit.
 11. The firearm according to claim 1, wherein a front shaft is designed to fit onto the housing.
 12. The firearm according to claim 1, wherein the receiver further comprises at least one rail.
 13. The firearm according to claim 12, wherein the at least one rail is substantially parallel to an axis of the barrel.
 14. The firearm according to claim 12, wherein the accessory is attached to the at least one rail.
 15. The firearm according to claim 1, wherein the receiver is made of a metal, a plastic, or a metal-plastic combination.
 16. The firearm according to claim 1, wherein the receiver is a single piece.
 17. The firearm according to claim 1, wherein the receiver comprises more than one component.
 18. The firearm according to claim 1, wherein the receiver at least partially surrounds the housing.
 19. For use with a firearm, an adapter to attach at least one accessory, the adapter comprising: a housing that surrounds at least a portion of a barrel of the firearm, wherein the housing further comprises a cylindrical exterior surface and at least one circumferential formation; and a receiver attached to the housing, wherein the receiver further comprises an interior surface that at least in part matches the exterior surface of the housing and at least one bore through which a coupling mechanism is inserted to couple the receiver to the at least one circumferential formation of the housing.
 20. The adapter according to claim 19, wherein the receiver is rotatable with respect to the housing.
 21. The adapter according to claim 19, wherein the receiver is axially fixed with respect to the housing.
 22. The adapter according to claim 19, wherein the rotational alignment of the receiver is independent of the position of the housing.
 23. The adapter according to claim 19, wherein the housing is mechanically linked to the barrel.
 24. The adapter according to claim 19, wherein the housing is axially parallel to the barrel.
 25. The adapter according to claim 19, wherein the receiver further comprises an extension that engages a recess in a portion of the firearm to limit rotation of the receiver.
 26. The adapter according to claim 19, further comprising a second circumferential formation.
 27. The adapter according to claim 19, wherein the housing further comprises a protuberance that serves as a contact for the receiver unit.
 28. The adapter according to claim 19, wherein a front shaft is designed to fit onto the housing.
 29. The adapter according to claim 19, wherein the receiver further comprises at least one rail.
 30. The adapter according to claim 29, wherein the accessory is attached to the at least one rail.
 31. The adapter according to claim 19, wherein the receiver is made of a metal, a plastic, or a metal-plastic combination.
 32. The adapter according to claim 19, wherein the receiver at least partially surrounds the housing.
 33. A method of modifying a firearm that has a removable barrel, the method comprising: removing the barrel from a lock in the firearm; inserting a second barrel in place of the removed barrel; threading the housing into the lock to secure the barrel; mounting a receiver to the housing, wherein the receiver serves as an attachment for at least one accessory.
 34. The method according to claim 33, wherein the receiver is rotatable with respect to the housing.
 35. The method according to claim 33, wherein the receiver is axially fixed with respect to the housing.
 36. The method according to claim 33, wherein the rotational alignment of the receiver is independent of the position of the housing.
 37. The method according to claim 33, wherein the receiver further comprises an extension that engages a recess in a portion of the firearm to limit rotation of the receiver.
 38. The method according to claim 33, wherein a front shaft is designed to fit onto the housing.
 39. The method according to claim 33, wherein the receiver further comprises at least one rail.
 40. The method according to claim 39, wherein the accessory is attached to the at least one rail. 